High
30 60 70 on Chaffoteaux Serelia 24 MFFI

Your boiler has lost its connection to the sensor that monitors your hot water cylinder temperature, causing it to stop heating your water.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Thermistor cylinder open

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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